The shot (medroxyprogesterone acetate) is an injection of the progesterone hormone. Progesterone makes the mucus at the cervix thick so the sperm cannot get through to the egg, and it can thin the lining on your uterus. It may prevent the release of an egg as well. It is given once every 12 weeks and is over 99% effective.


  • You won't have to think about your birth control
  • It works every minute of every day
  • It could make crampy periods better


  • You need a shot every 12 weeks
  • It can cause irregular bleeding or stop your periods - this is normal
  • It might make you gain weight
  • It might make acne worse
  • It could make chronic depression worse
  • Once it is given, there is no way to take it out - it must wear off